Zoo keepers have begun a daily monitoring of the UK's giant panda couple as mating season approaches.
Edinburgh Zoo hopes Tian Tian and Yang Guang will produce a cub this year as the creatures start to show the tell-tale signs they are ready to breed.
There was disappointment last year when the pair did not mate and though Tian Tian was artificially inseminated she lost her foetus at late term.
Panda reproduction is a notoriously tricky process, with females only ovulating once a year.
One of the UK's two giant pandas celebrated his ninth birthday today in Edinburgh Zoo.
Yang Guang tucked into a special cake in the shape of a panda head, as well some bamboo presents.
His birthday comes just ten day's before the UK's other giant panda, female Tian Tian, who will turn nine on August 24.
Tian Tian (Sweetie) and Yang Guang (Sunshine) are the first giant pandas to live in the UK for 17 years and Edinburgh Zoo will be their home for the next 10 years.